With a known device of this type, which is described in the publication "WlB `wasser, luft und betrieb`" 7-8/79, p. 16, the filter elements are mounted in a common housing on a common filter carrier plate, which has filter connections connected here and there with the inside of each filter element. The orifice of a rotary valve can be brought into connection as desired wiith one of the filter connections in the filter carrier plate. This device has a complicated structure and is difficult to service, since it must be completely dismantled for servicing.
One known hoist device for power vehicles, shown in German patent No. 516,045, has a rotary slide valve constructed as a switching valve and a valve housing surrounding this slide valve with a plurality of radial boreholes. The lengthwise borehole in the switching valve can be brought into connection with one of the radial boreholes in the housing as desired through a radial borehole in the switching valve. The axial borehole of the switching valve can be brought into communication with any other radial borehole in the housing by turning the valve element.